March 2025: Delivered a CI workflow improvement for EspressoSystems/optimism-espresso-integration by migrating the changed-files detector in the docker-build-scan workflow from tj-actions/changed-files to step-security/changed-files. The update preserves existing functionality while enhancing reliability and maintainability of the CI pipeline. This work is anchored by commit 1a5587d0fa1a1fbc8489cf5dd81d9a8384b4da72 with the message 'use step-security replacement for tj-actions/changed-files'. No major bugs were fixed this month; the focus was on stabilizing CI and enabling easier future changes. Impact: reduced CI fragility, faster issue diagnosis, and clearer ownership of the changed-files logic across the repository. Technologies/skills demonstrated: GitHub Actions, CI/CD workflow configuration, action migration, and version-controlled automation.